Solar radiation is incident on the front surface of athin plate with direct and diffuse components of 300 and 250W/m2, respectively. The direct radiation makes a 30° anglewith the normal of the surface. The plate surfaces have a solarabsorptivity of 0.63 and an emissivity of 0.93. The air temperatureis 5°C and the convection heat transfer coefficient is20 W/m2·K. The effective sky temperature for the front surfaceis -33°C while the surrounding surfaces are at 5°C forthe back surface. Determine the equilibrium temperature ofthe plate.

Solar radiation is incident on the front surface of athin plate with direct and diffuse components of 300 and 250W/m2, respectively. The direct radiation makes a 30° anglewith the normal of the surface. The plate surfaces have a solarabsorptivity of 0.63 and an emissivity of 0.93. The air temperatureis 5°C and the convection heat transfer coefficient is20 W/m2·K. The effective sky temperature for the front surfaceis -33°C while the surrounding surfaces are at 5°C forthe back surface. Determine the equilibrium temperature ofthe plate.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.61P

See similar textbooks

Similar questions

Determine the rate of radiant heat emission in watts per square meter from a blackbody at (a) 15C, (b) 600C, and (c) 5700C.
Two concentric spheres of diameters D1 = 15 cm and D2 = 25 cm are separated by air at 1 atm pressure. The surface temperatures of the two spheres enclosing the air are T1 = 350 K and T2 = 275 K, respectively, and their emissivities are 0.75. Determine the rate of heat transfer from the inner sphere to the outer sphere by (a) natural convection and (b) radiation.
Consider a black spherical ball, with a diameter of 25 cm, is being suspended in air. Determine the surface temperature of the ball that should be maintained in order to heat 11.7 kg of air from 20°C to 30°C in the duration of 5 minutes.Given: cv = 718 J/kg∙K Stefan-Boltzmann constant (σ) = 5.67 × 10–8 W/m2∙K The surface temperature of the ball is Ts = _____ °C.
According to an Atomic Energy Commissionreport, a hydrogen bomb can be approximated as a large fireball at a temperature of 7200 K. You are to assess theimpact if such a bomb exploded 5 km above a city. Assumethe diameter of the fireball to be 1 km, and the blast to last15 s. Investigate the level of radiation energy people, plants,and houses will be exposed to and how adversely they will beaffected by the blast.
Consider a three-square-foot black body plane surface at a temperature of 76°F,calculate the heat transfer by radiation to the surface from another three-squarefoot black body plane directly above and parallel to the first at temperatures of1510°F.A. 76,431 Btu/hr B. 76,631 Btu/hrC. 76,831 Btu/hr D. 76,931 Btu/hr
2. A thin aluminum sheet with an emissivity of 0.15 on both sides is placed between two very large parallel plates, which are maintained at uniform temperatures T1 = 900 K and T2 = 650 K and have emissivities ?1 = 0.5 and ?2 = 0.8, respectively. Determine the net rate of radiation heat transfer between two plates per unit surface area of the plates and compare the result with that without the shield
2.A person stands in front of a fire at 650°C in a room where air is at 5°C. Assuming the body temperature to be 37°C and a connection coefficient of 6 W/m²K, the area exposed to convection as 0.6m2, determine the net heat flow from the body. The fraction of radiation from the fire of 1m² are reaching the person is 0.01
A thin aluminum sheet with an emissivity of 0.14 on both sides is placed between two very large parallel plates maintained at uniform temperatures of T1=720 K and T2=560 K. The emissivities of the plates are ɛ1=0.76 and ɛ2=0.85. Determine the net rate of radiation heat transfer between the two plates per unit surface area of the plates, and the temperature of the radiation shield in steady operation.
A 2-m-internal-diameter double-walled spherical tank is used to store iced water at 0°C. Each wall is 0.5 cm thick, and the 1.5-cm-thick air space between the two walls of the tank is evacuated in order to minimize heat transfer. The surfaces surrounding the evacuated space are polished so that each surface has an emissivity of 0.15. The temperature of the outer wall of the tank is measured to be 20°C. Assuming the inner wall of the steel tank to be at 0°C, determine (a) the rate of heat transfer to the iced water in the tank and (b) the amount of ice at 0°C that melts during a 24-h period.
A group of 25 power transistors, dissipating 1.5 W each, are to be cooled by attaching them to a black-anodized square aluminum plate and mounting the plate on the wall of a room at 30°C. The emissivity of the transistor and the plate surfaces is 0.9. Assuming the heat transfer from the back side of the plate to be negligible and the temperature of the surrounding surfaces to be the same as the air temperature of the room, determine the size of the plate if the average surface temperature of the plate is not to exceed 50°C.
A 5-in-diameter spherical ball is known to emit radiation at a rate of 550 Btu/h when its surface temperature is 950 R. Determine the average emissivity of the ball at this temperature.